First Lady of The United States Michelle Obama addresses the Democratic National Convention on its opening night at the Time Warner Arena in Charlotte, N.C., on Tuesday, September 4, 2012. (Andrew Geraci/ The Washington Times)

Ken Yarmosh, of Charlotte, N.C. walks up Stonewall Street in Charlotte, N.C. on Tuesday, Sept. 4, 2012 carrying a cross. He said he is at the Democratic National Convention to remind people that what they are looking at is political and temporal, and that the true hope and change is Jesus Christ. (Barbara L. Salisbury/The Washington Times)

A woman takes a picture of an ice sculpture that says "Middle Class" on Tuesday, Sept. 3, 2012 in Marshall Park in Charlotte, N.C., which has been taken over by the Occupy movement during the Democratic National Convention. The sculpture, which was made by artists Ligorano and Reese, is called "Morning in America" and is supposed to represent the fact that the middle class is disappearing like ice. (Barbara L. Salisbury/The Washington Times)

Lauren Digioia, center, of New York City, who is a member of the Occupy Wall Street movement, talks to fellow protesters on the streets of Charlotte, N.C. outside the Democratic National Convention. Although they were given a designated "free speech zone," protesters preferred to stay in the street. (Barbara L. Salisbury/The Washington Times)

Police officers use their bicycles to create a perimeter to keep protesters inside a designated area along Stonewall Street in Charlotte, N.C. Protesters are allowed to march and demonstrate at the Democratic National Convention but are being kept well away from DNC venues. (Barbara L. Salisbury/The Washington Times)

A police officer pushes a protester back into the protest zone created by police in the streets of Charlotte outside the Democratic National Convention. (Barbara L. Salisbury/The Washington Times)

Protesters pull out a tent and cram 13 people inside of it, chanting, "This is affordable housing!" and then, "Out of the tents and into the streets!" in Charlotte, N.C. There are hundreds of Occupy protesters in town for the Democratic National Convention. (Barbara L. Salisbury/The Washington Times)

Rep. Debbie Wasserman Schultz, D- Fla., Chair of the Democratic National Committee gavels in the Democratic National Convention at the Time Warner Arena in Charlotte, N.C., on Tuesday, September 4, 2012. (Andrew Geraci/ The Washington Times)

The third-grade class of the W.R. O'Dell Elementary School in Concord, N.C., recite the Pledge of Allegiance at the opening of the Democratic National Convention in Charlotte, N.C., on Tuesday, Sept. 4, 2012. (Andrew Geraci/The Washington Times)

Amber Riley, singer/songwriter and "Glee" actress, sings the National anthem before a color guard of Disabled American Veterans of The Stanly County Chapter 12 Honor Guard the Democratic National Convention. (Andrew Geraci/ The Washington Times)

Presentation of Rules Committee Report from Co-Chairs The Honorable Kamala D. Harris State Attorney General of California and The Honorable Martin O'Malley Governor of Maryland at the Democratic National Committee gavels in the Democratic National Convention. (Andrew Geraci/ The Washington Times)

Texas delegate Trisha Frederick, of Houston, Tex., listens to speeches at the Democratic National Convention. (Barbara Salisbury/ The Washington Times)

Tim Kaine, Candidate for the US Senate from Virginia, former Governor of Virginia and former Chairman of the Democratic National Committee addresses the Democratic National Convention. (Barbara Salisbury/ The Washington Times)

Nevada delegate and National co-chair of the Re-elect Obama campaign, Loretta Harper, listens to speeches at the Democratic National Convention. (Barbara Salisbury/ The Washington Times)

Ken Salazar, Secretary of the Interior, is seen on the large screen above the stage. (Andrew Geraci/ The Washington Times)

William Gordner, of Atlanta, Ga. emerges from the Google Photo Booth. (Barbara Salisbury/ The Washington Times)

Lt. Col. Tammy Duckworth, candidate for the US House of Representatives for Illinois and former Assistant Secretary of the US Department of Veterans Affairs leaves the stage after addressing the Democratic National Convention. (Andrew Geraci/ The Washington Times)

New Mexico delegate Priscilla Chavez, of Las Cruces, N.M. cheers on the first night of the Democratic National Convention. (Barbara Salisbury/ The Washington Times)

Rahm Emanuel, Mayor of Chicago, Ill., former White House Chief of Staff addresses the Democratic National Convention at the Time Warner Arena. (Andrew Geraci/ The Washington Times)

Convention volunteer Regina Davidson wipes away a tear while watching a speech at the Democratic National Convention. (Barbara Salisbury/ The Washington Times)

Kal Penn, actor/producer and former Associate Director of the White House Office of Public Engagement addresses the Democratic National Convention. (Andrew Geraci/ The Washington Times)

View of the first night of the Democratic National Convention at the Time Warner Arena in Charlotte, N.C., on Tuesday, September 4, 2012. (Andrew Geraci/ The Washington Times)

Maryland Governor Martin O'Malley addresses the Democratic National Convention at the Time Warner Arena in Charlotte, N.C., on Tuesday, September 4, 2012. (Andrew Geraci/ The Washington Times)

Joaquin Castro, right, brother of Julian Castro, left, Mayor of San Antonio, Tex. introduces him for the keynote address on the opening night of the Democratic National Convention. (Andrew Geraci/ The Washington Times)

Julian Castro, mayor of San Antonio, delivers the keynote address on the opening night of the Democratic National Convention in Charlotte, N.C., on Tuesday, Sept. 4, 2012. (Andrew Geraci/The Washington Times)

First Lady of the United States Michelle Obama addresses the Democratic National Convention on its opening night at the Time Warner Arena in Charlotte, N.C., on Tuesday, September 4, 2012. (Andrew Geraci/ The Washington Times)

First Lady of the United States Michelle Obama addresses the Democratic National Convention on its opening night at the Time Warner Arena in Charlotte, N.C., on Tuesday, September 4, 2012. (Barbara Salisbury/ The Washington Times)

CHARLOTTE, N.C. — First lady Michelle Obama pleaded with voters Tuesday to reward her husband with re-election, telling delegates at the Democrats’ convention that President Obama comes from humble beginnings but was able to reach the White House by taking advantage of the same kind of social safety net he defends on the campaign trail.

Democrats convened their nominating convention with a mix of sharp barbs against Republican presidential nominee Mitt Romney and his personal wealth, and a defense of Mr. Obama’s first-term record on everything from health care to gay rights.

Seeking to unify Democrats and win over independents with the inspirational story that powered Mr. Obama to an historic election in 2008, Mrs. Obama told delegates her husband is still pushing for the vision voters embraced four years ago.

She said also the president’s push for government programs is personal because they are the foundation he himself used to climb to the White House.

“He believes that when you’ve worked hard, and done well, and walked through that doorway of opportunity, you do not slam it shut behind you — you reach back and you give other folks the same chances that helped you succeed,” she said, her pointedly personal appeal winning chants of “Four more years” from the frenetic crowd.

Democrats sought to turn the election into a choice between Mr. Obama and Mr. Romney, rather than a referendum on the president — which would be bad news for the incumbent, who polls show many voters are wary of returning to Washington.

“We’re making progress, and now we need to make a choice,” San Antonio Mayor Julian Castro said in the convention’s keynote address, delivered later Tuesday night. “It’s a choice between a country where the middle class pays more, so that millionaires can pay less — or a country where everybody pays their fair share.”

Mr. Castro becomes the first Latino to deliver a keynote address — a move aimed at highlighting the diversity of the Democratic Party as Mr. Obama tries to rally a disparate coalition of black and Hispanic voters, women and gay-rights supporters that can give him a majority.

The convention begins as polls show the race between Mr. Obama and Republican opponent Mitt Romney to be a tight affair. The Real Clear Politics average of polls gives Mr. Obama a lead of just a tenth of a percent — though the president also holds razor-thin leads in most battleground states.

Most important, Mr. Romney did not get a boost from his convention last week, according to the latest round of polls.

Just as Ann Romney, wife of Mr. Romney, did at Republicans’ convention last week, Mrs. Obama humanized her husband, pointing to him as a devoted husband and a good father who shared the same struggles as other Americans when they were a newlywed couple.

She talked about Mr. Obama picking her up for dates in a car that had a rusted-out bottom, and about their upbringings in families of limited means.

“We were so young, so in love, and so in debt,” she said — but she put a political point on the message, saying that’s why Mr. Obama supports increasing student aid.

“In the end, for Barack, these issues aren’t political, they’re personal,” she said.

The election is shaping up as a clash between dramatically different views of government power and the social safety net.

Mr. Romney is running on a message of cutting spending and lowering government regulations, arguing that smaller government will unleash the private sector to create jobs, which will create economic security for everyone.

But Mr. Obama argues a stronger safety net will provide more even opportunities for everyone.

“Like many of you, I watched last week’s Republican convention. They told a few stories of individual success,” Mr. Castro said. “But the question is, how to we multiply that success? The answer is President Barack Obama.”

Democrats pointed to a series of laws he’s signed, including health care and the Lilly Ledbetter Act, which overturned a Supreme Court decision and made it easier for women to sue over pay discrimination.

“It says something about his priorities that the first bill he would put his name on, has my name on it too,” Ms. Ledbetter said in addressing the convention.

She also challenged Mr. Romney to take a stand on the Paycheck Fairness Act, which would open up still more opportunities to sue over pay discrimination.

Mr. Romney’s campaign refused to respond to repeated requests from The Washington Times to take a stand on the legislation, which Senate Republicans blocked in a filibuster earlier this year.

Mr. Romney was a constant focus of the attacks, including some biting criticism from Massachusetts Gov. Deval Patrick, who succeeded Mr. Romney as governor there and accused him of having left a “deficit hole” and leaving pensions and schools underfunded.

“As governor he was a lot more interested in having the job than in doing the job,” Mr. Patrick said.

Mr. Romney’s campaign defended his record, saying he oversaw an “historic turnaround” in the state.

“Under Governor Romney’s leadership, Massachusetts’ unemployment rate fell to 4.7 percent, the economy created tens of thousands of new jobs, and the state’s rainy day fund grew to over $2 billion,” said campaign spokesman Andrea Saul. “If President Obama had half of Mitt Romney’s record, he’d be running on it.”

Republicans also seized on the Treasury Department’s announcement Tuesday that the government’s debt now tops $16 trillion. Mr. Obama has increased debt more in his three-and-a-half years in office than President George W. Bush did in eight years.

“Of all the broken promises from President Obama, this is probably the worst one because this debt is threatening jobs today, its threatening prosperity today and it is guaranteeing that our children and grandchildren get a diminished future,” said Republican vice presidential nominee Rep. Paul Ryan.

Democrats shied away from the federal budget during their opening session, instead focusing on social issues such as abortion and women’s and minority rights.

In opening the convention on Tuesday, delegates voted by voice to adopt their platform, becoming the first major political party to specifically endorse same-sex marriage as an option. The platform also defends labor unions and demands a higher minimum wage; calls for stricter gun control laws; and lays out a plan to grant illegal immigrants a full path to citizenship.

But the platform is silent on issues such as drone attacks in the war on terror, including against American citizens who were targeted without ever facing a trial.

And while it includes a call for statehood-like rights for the District of Columbia, the platform doesn’t mention statehood specifically.

The party further disappointed leaders in the city, which is overwhelmingly Democratic, when they did not grant any time for speakers to talk about D.C. statehood rights from the podium — the first time in two decades they’ve failed to carve out a speaking slot, according to Delegate Eleanor Holmes Norton.

“Failing to give the District of Columbia a voice at the convention this year, in particular, is a bitter pill to swallow,” she said.